The Red Pitaya "ecosystem" which contains most of the specialized software that runs on the Red Pitaya does not use any kind of package manager. You usually replace the entire contents of the FAT32 partition (which is mounted as /opt/redpitaya) with a new ecosystem - this is also what the bazaar updater does under the hood.
The Ubuntu distro that makes up the bulk of the OS uses the standard Ubuntu package manager (dpkg and apt) and repositories for ARM.